Internally cooled turbine blades may include passages and vanes (air deflectors) within the blade. These hollow blades may be cast. In casting hollow gas turbine engine blades having internal cooling passageways, a fired ceramic core is positioned in a ceramic investment shell mold to form internal cooling passageways in the cast airfoil. The fired ceramic core used in investment casting of hollow airfoils typically has an airfoil-shaped region with a thin cross-section leading edge region and trailing edge region. Between the leading and trailing edge regions, the core may include elongated and other shaped openings so as to form multiple internal walls, pedestals, turbulators, ribs and similar features separating and/or residing in cooling passageways in the cast airfoil.
U.S. Pat. No. 6,720,028 issued to Haaland on Apr. 13, 2004 shows a method of making an impregnated ceramic core especially useful in casting of hollow gas turbine engine blades and vanes (airfoils). In particular, Haaland shows a fired, porous ceramic core for use in investment casting a hollow gas turbine blade where the core has a configuration of internal cooling passages to be formed in the blade casting.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventors.